I definitely thought this rule was already in effect--I had a
`build/.gitignore` that contained just `*`. Unfortunately, that makes
git ignore the .gitignore file itself, so it was never added to the
repo...
It was never supposed to be part of the repo, and currently accounts for
at least half of the .git directory's size. We need to nip it in the bud
before `git clone` times become unmanageable!